Objective:To evaluate the effect of down-regulation of RACK1 expression on growth and radiosensitivity of oral squamous cell carcinoma cells.Methods:The shRNA vector for RACK1 gene was constructed and transfected into HSC-3 cells by lipofectamine. The stably-transfected cell line was obtained by constructing G418. The expression levels of RACK1 mRNA and protein were detected by RT-PCR and Western blot. The cell proliferation was detected by CCK8 assay. Cell apoptosis was examined by flow cytometry. The invasive and metastatic capabilities of cancer cells were assessed by cell invasion assay in vitro.The effect of X-ray irradiation combined with down-regulation of RACK1 expression upon cell proliferation was assessed by clone formation assay. The xenograft tumor nude mouse model was established to observe the inhibitory effect of down-regulating RACK1 gene expression combined with X-ray irradiation on oral squamous cell carcinoma. Results:RT-PCR revealed that the expression level of RACK1 mRNA of transfected HSC-3 cells was significantly down-regulated ( P<0.05). Western blot showed that the expression level of RACK1 protein was significantly down-regulated ( P<0.05). CCK8 assay demonstrated that down-regulation of RACK1 expression could remarkably inhibit the growth of HSC-3 cells ( P<0.05). RACK1 gene shRNA interference combined with X-ray irradiation significantly enhanced the apoptosis rate of HSC-3 cells ( P<0.05). The number of invasion cells in vitro in the RACK1 silencing group was evidently decreased ( P<0.05). Clone formation assay showed that the survival fraction in the shRACK1 group was significantly lower than that in the control group. The sensitization enhancement ratio was 1.37(ratio of D 0 value). Xenograft tumor experiment in nude mice showed that tumor growth was significantly inhibited in the shRACK1 group, the tumor volume was significantly decreased and the tumor mass was significantly lower than those in the control group (all P<0.05). Conclusion:Down-regulating RACK1 expression can enhance the radiosensitivity of oral squamous cell carcinoma cells, providing novel thinking to improve the radiosensitivity of oral squamous cell carcinoma.

A sequential extraction procedure has been proposed for the evaluation of the speciation of heavy metals including Cd,Cu,Pb and Zn in sediments from mariculture area,and the speciation of heavy metals was separated and defined as acid soluble fraction,reducible fraction,fraction bound organic matter,fraction bound sulfides and residual fraction. Matrix effects of high salinity on the determination of heavy metals in sediments were eliminated by matrix matching and internal standard methods when inductively couple plasma optical emission spectroscopy (ICP-OES) and mass spectroscopy (ICP-MS) were used,respectively. The results showed that the measured values of marine sediment reference materials were consistent with the standard values when the digestion solutions were determined after dilution. The extraction results of the prepositional extraction procedure and European Community Bureau of Reference Program (BCR) procedure were compared and the selectivity of extractants was investigated. The preliminary studies indicated that this sequential extraction procedure was applicable for evaluating the speciation of heavy metals in sediment with organic substances pollution and eutrophication,especially for fraction bound organic matter and fraction bound sulfides.

Objective To investigate the accuracy of CTVision image-guided stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC).Methods 10 lung SBRT patients were imaged with CTVision before and after irradiation for acquiring and analyzing the three-dimensional set-up error data sets in our department from October 2010 to May 2012.Gross tumor volumes (GTVs) were contoured on pre-and post-SBRT CT sets and combined for generating internal gross tumor volumes (IGTVs).Planning target volume (PTV) margin was calculated,and IGTVs and PTVs were compared for off-line verification of accuracy of SBRT.A paired t-test statistical analysis was conducted with the datasets using SPSS 17.0.Results 80 CT image sets were totally obtained.Setup errors was significant difference before and after radiotherapy in the left-right,superior-inferior and anterior-posterior directions,that were (-0.10±1.30) mmand (-0.15±1.31) mm (P=0.720),(0.18±1.32) mm and (0.18±1.43) mm (P =1.000) and (-0.08 ± 1.19) mm and (-0.13 ± 1.18) mm (P =0.750),respectively.IGTVs of ten patients were smaller than corresponding PTVs (13.53 cm3 and 37.84 cm3,P =0.000).Conclusion Accuracy and safety of SBRT could be verified by imaging with CTVision before and after delivery for non-small cell lung cancer.